Mechanically latched contactor



April 4, 1967 w. F. DEHN 3,312,808

MECHANICALLY LATCHED CONTACTOR Filed March 17, 1965 4 Sheets-Sheet l agge0 35 56 34? 4@ l' E; INVENTOR l: 50 @Z 5545 WILLIAM F. DEHN J |31 54 Y56 47 57 jiu: 57

av (7 (i 40 4 35 April 4, 1967 w. F. DEHN 3,312,808

MECHANICALLY LATCHED -CONTACTOR Filed Match 17, 1965 v 4 Sheets-Sheet 2INVENTOR WILLIAM F. DEI-4N BY e.

Filed March 17, 1965 April 4 v1967 w. F. DEHN y 3,312,808

MECHANICALLY LATCHED CONTACTOR 4vSheets-'Sheet 5 ZSQ 57 INVENTOR WILLIAMF. DEHN April 4, 1967 w. F. DEHN 3,312,808

MECHANI CALLY LATCHED CONTACTOR Filed March 17, 1965 4 Sheets-Sheet 4325 325 53/ 338 55733 338 335 55o y 33o 337 34 342 345 356 l 5+ 354 324342 52' M336 3Go 554 336 3 @s se? 3% 35e@ 35 +9 3&7 364 s@ 30, 5 3545305 50( 304 320 3 530242) 32 5/5 321 2, :21 3oz v 3 58 5/3 als @f5 3l@VON X 340 E Ex( a 35 54s s E 3 554 33e lNvl-:NTOR

WILLIAM F. DEHN I 365 3&2 34. 3.676a Bv 3@ @und $567 30/ l @s 1 5@United States Patent C 3,312,808 MECHANICALLY LATCHED CNTACTOR WilliamF. Dehn, Wauwatosa, Wis., assignor to Allen- Bradley Company, Milwaukee,Wis., a corporation of Wisconsin Filed Mar. 17, 1965, Ser. No. 440,573Claims. y(Cl. 200-169) This invention is related to an improvedmechanical latch for mechanically holding or locking electricalswitching devices, e.g. switches, relays, con-tactors, etc., in adesired contact open or contact closed position in response, `forexample, to an external force or energization of a magnetic coiltherein. The parti-cular control circuitry used for coil energization isa matter of choice to include, but not limited to, two-wire control.

-While the concept of mechanically latching electrical switch deviceswithin the scope of this invention has been investigated by others, eachknown latch is complex, unreliable and/or unpredictable. The presentinvention avoids each of these disadvantages and thus satisfies thelongstanding need for -a simple, efiicient and reliable mechanicallatch.

The advantages of a mechanical latch are most evident when consideringan electrically actuated switch or contactor which is to remain in itsactuated position for a period of time. Through mechanical latching amagnet coil of the switch is energized only when it is desired to openor cl-ose the switch contacts with necessary latch action; therebyeliminating the possibility of noise originating in the initiatingcircuit, overheating of the initiating circuit, etc. Lighting circuits,especially night lighting, serve as good examples for application of theinvention.

One object of the invention is to provide a simple -and effectivemechanical latch for electrical switch devices with two moving elementswhich are maintained in abutting relation by a spring; one element whichlocks into a holding structure and is simultaneously primed forunlocking.

A more specific object is to provide the above described mechanicallatch wherein a single spring connecting the latch and latch actuator isused to bias the latch toward a locking position when required and yettoward an unlocked position when locked.

A further object is to provide a simple mechanical latch with a minimumof moving parts which results in more reliable and longer use.

Another object is to provide a mechanical 'latch which is compact andeasily adaptable to electrical switch devices of all descriptions.

Another object is t-o provide a most eicient mechanical latch with aminimum of moving parts and minimum surface contact.

A still further object is to provide a more economical latch forelectrical switch devices, particularly in view of the latch simplicity,

A still further object is to provide a simple mechanical latch for -anelectromagnetic device which can accommodate any desired control circuitto include two-wire control actuated by means of a simple single poleswitching means.

Other objects of the invention are and will become apparent from thespecification herein.

FIG. l is a front, cutaway view of a latch embodiment of this inventionin combination with an electromagnetic device represented by a contactorshown in an inactive or normal operating position.

FIG. 2 shows a side view of the latch yand contactor combination takenalong line 2 2 of FIG. 1.

FIG. 3 shows an enlarged fragmentary view of FIG. l

after the magnet coil has -been energized, thus lifting ythe armature,contact carrier and attached latch to a position above the mechanicallatch locking position; and further showing line -contact between thelatch lock detent and the beveled catch surface.

FIG. 4 shows an enl-arged fragmentary view of FIG. l with the latchcammed to its holding position after the coil has been deenergized.

FIG. 5 shows an enlarged fragmentary view of a combination similar toFIG. l, viz. a contactor in combination with a second latch embodimentof the invention, the combinati-on shown in the same position as FIG. 1and taken along line 5-5 of FIG. 8.

FIG. 6 shows the combination of FIG. 5 after coil energization andconsequential rise of armature contact carrier and attached latch to aposition of line contact Abetween the latch lock detent and the beveledcatch surface comparable to FIG. 1.

FIG. 7 shows the combination of FIG. 5 in the latch locking positionafter the coil has been de-energized comparable to FIG. 4.

FIG. 8 shows a side view of the combination of FIG. 5 taken along line 88 of FIG. 5.

FIG. 9 shows an enlarged fragmentary view of a cornbin-ation similar toFIG. l including a still further latch embodiment with a portion of acontactor in an inactive or normal operating position comparable toFIGS. l and 5.

FIG. l0 shows the combination of FIG. 9 after coil energization andconsequential rising of the armature, contact carrier and attached latchto a position comparable to FIGS. 3 and 6. K

FIG. ll shows the the combination of FIG. 9 after coil de-energizationwith the latch in its locking position, i.e., the latch lock detent insurface contact with the beveled catch surface.

FIG. 12 shows a side view of FIG` 9 as taken along line 12-12 of FIG.,9.

FIG. 13 shows a cross-sectional, fragmentary view of the mechanicallatch feature of this invention used with an electrical switch.

FIG. 14 shows a cross-sectional, fragmentary view of the combination inFIG. 13, but with the switch mechanism having been tripped by downwardmovement of the switch actuator and the latch mechanism having .beenmoved to a position where line contact exists between the latch andlatch catch surface.

FIG. 15 shows a partial cross-sectional, vfragmentary view of the latchin FIG. 13 as the latch would appear in its latched or locked position.

FIG. 16 shows a fragmentary, cross-section, side view of the mechanicallatch in combination with the switch as shown in FIG. 13. .l

While only three embodiments ofthe latch mechanism feature of thepresent invention are shown in the drawings, the invention is notintended to be limited in scope to these embodiments. Moreover, theinvention is not limited to a particular electric switch device,v letalone a particular electromagnetic device, although the drawingsillustrate a specific contactor and switch. Fin-ally, the number ofmechanical latch assemblies used with a switch is a matter of choice toone skilled in the art, eg., only one latch assembly, properly locatedwith respect to operating balance would be sutlicient in the case of thecontactor combination shown in FIGS. 1-l2.

Turning to the drawings, the electromagnetic device, depicted here as acontactor, will be described by means of its basic elements since onlythe fundamental operation of the contactor is necessary to understandits relationship to the latch assembly. Referring to FIGS. 1 and 2 amounting plate 1 is attached to the frame 2 and forwardly extending arms3 and legs 4, which support the operating portions of the contactor.Contact carrier 5 slidably supported by the forwardly extending whenmagnet coil 14 is energized.

' -The slidable carrier 5 moves between two extreme positions with thefirst or lower extreme position occurring during inactivity of themagnet coil 14, i.e., a nor- -mal operating position (see FIG. l), whilethe second position or upper extreme position occurs when the magnetcoil 14 has been energized and laminated magnet armature 12 abuts xedlaminated yoke 13. It should be noted that this lower extreme positionis limited by Contact carrier abutting forwardly extending leg 4 (FIG.1). Somewhere between these two extreme positions, the movable contacts15 and 16which are secured to the contact carrier 5 by conductingSpanner 17, abut stationary contacts 18 and 19 which are conductivelyattached to terminals 20 by means of contact elements 21. The terminalshave clamping screws 22 so as to hold line wires (not shown) attachedthereto. Compression springs 25 located in contact cages 6 abut theconducting Spanner 17 on its underside (the spanner also being locatedwithin the contact cages 6) so that upward movement of the contactcarrier 5 is permitted after movable contacts 15 and 16 have abuttedstationary contacts 18 and 19, i.c., spanner 17 compresses spring 25after the contacts are closed. Deenergization of magnet coil 14, whetherimmediately upon abutting contact of the armature 12 and fixed yoke 13or a controlled time thereafter, will interrupt the magnetic field whichresults in separation of the armature 12 from fixed yoke 13 andconsequential downward movement of the contact carrier 5. Additionalfeatures of the `contacter shown in the drawings include arc chamber 26,arc chamber cover 27, molded cover 28 and auxiliary switch 29' with itsactuating tongue 30.

The latch assembly 35, of which two are shown in FIG. l, isfundamentally made up of three elements, viz. latch 36, latch actuator37 plus outer and inner fixed latch guides 38 and 39, respectively.These guides are part of a wrap-around casing 4G for the latch assembly35 which is attached to forwardly extending legs 4 at 41. Latch actuator37 is attached to the contact carrier 5 by means of connecting element42, mounting ears 43 and bolts 44 to provide simultaneous movementtherewith; while concave cam surface 45 of the .latch actuator 37contacts latch 36 for movement thereof. Connecting elements 42 alsoinclude holding plate 46 which limits downward motion of the contactcarrier by abutment of the latch 36 in its locking position (see FIG.4), although it should be noted that various expedients can beused tolimit this downward motion including spring 25.l.-' ;.The latch 36,itself, consists of a free end 47 abutting the cam surface 45 of theactuator 37, a latch lock detent 48 and a protrusion 49 which includesreset surface 50 engageable with a bottom surface 54 of window 55,blanked from outer latch guide 38. The shape of the latch 36 is signifiycant for two reasons: (1) to permit pivoting about the catch 56, i.e.thelatch center of gravity isV preferably located outside of the latchmass above the catch, and (2) the latch lock detent 48 should permitline contact with the catch 56 before the latch 36 pivots about thecatch, i.e. when the latch is biased toward the inner latch guide 39`(sce FIG. 3). Obviously, the latch shape must permit y desired movementthereof. f

l Connecting latch 36 and latch actuator 37 are tension spring 57mounted on pins 58 and 59 which are respectively attached to the latchand latch actuator (see FIG. 2). The wrap-around casingprovides-surfaces for both holding the latch in its locking position,i.e. the beveled catch surface 60 of catch 56, and for resetting thelatch 36 after unlocking, i.e. bottom surface 54 in window 55 `whichabuts reset surface of protrusion 49. Y

The operation of the structure shown in FIGS. 1 thru 4 is as follows:When the contactor rests in the normal, inactive position of FIG. 1, thecontact carrier 5 is in its lower extreme position as Iare the movablelatch assembly parts (36 and 37) due to direct connection the-rebetween,viz. connecting element 42 and mounting ears 43. Upon energizing thefixed, magnet coil, the movable, laminated magnet armature 12 movestoward the fixed, laminated yoke 13 carrying with it the Contact carrier5 and movable latch assembly parts. While electrical and mechanicalcontact between movable contacts 15 and 16 and stationary contacts 18and 19 is made during the armature movement toward the yoke 13, theupward movement continues toward yoke abutment by virtue of the factthat movable contacts 15 and 16 are spring supported. Near or at theupper limit of arm-aturemovemcnt, i.e. the extreme upper position, thelatch locking detent 48 rises above the catch 56 of the inner latchguide 39 as shown in FIG. 3, whereupon the bias of the tension spring 57pulls the latch against the inner latch guide 39. The contact carrier 5may continue on to an upper extreme position (not shown) although thecontactor can be so designed that the upper extreme position is achievedwhen the -latch 36 first contacts the inner latch guidel39, (FIG. 3).

At this point in the locking sequence, the circuit through the movablecontacts 15 and 16 and stationary contacts 18 and 19 is complete as theenergized magnet coil 14 holds the magnet armature 12 and fixed yoke 13in abutting relationship, However, by the use of the mechanical latchfeature of this invention, the -magnet coil circuit may be deenergizedwithout interrupting the electrical connection through the line contacts15, 16 and 18, 19, c g. by the control of a two-wire coil circuit. Toaccomplish this end, the current through the coil 14 is interruptedcausing the contact carrier 5 and its attached latch actuator 37 to movedownwardly (see FIGS. 3 and 4), This downward movement brings the latchlock detent 48 and inner guide catch 56 into line contact (if suchcontact is nonexistent) as shown at 62 in FIG. 3; while further downwardmovement of the latch actuator 37 results in separation of ror reducedabutting pressure between the latch free end 47 and the actuator 37.vLatch free end 47 is therefore free to move toward the inner guide 39as the latch center of gravity causes the latch to pivot on beveledcatch surface until surface contact is made between the latch lockdetent 48 and beveled catch surface 60 of catch 56 (see FIG. 4). Furthermovement of the magnet armature 12 and contact carrier 5, after coildeenergization, is limited by holding plate 46 which abuts latch 36 inits locking position as shown in FIG. 4. Whether the latch free end 47abuts the cam surface 45 when the latch is in a locked position is amatter of design.

In the locked position, the tension spring 57 biases the upper `part oflatch 36 away from the inner guide 39 while the surface cont-act betweenlatch lock detent 48 and beveled catch surface 60 along with holdingplate 46 hold the latch in the locked position shown in FIG. 4.

When it is desired to interrupt the contacts 15, 16 and 18, 19, magnetcoil 14 is `again energized so as to lift the contact carrier 5 alongwith the moving parts of the latch assembly 36 and 37 to their upperposition thereby separating the latch lock detent 48 from`the beveledcatch surface 60. Due to the spring bias of latch 36 away from the innerguide 39, said separation results in immediate movement of the latchlock detent 48 and the upper portion of latch 36 down and away from theinner guide 39 as latch 36 pivots about the latch free end 47.Subsequent deenergization of magnet coil 14 will interrupt the magneticfield so as to cause the armature and moving latch assembly parts tomove downward to the position shown in FIG. l. During this downwardmovement, the reset surface 58 of latch protrusion 49 abuts the bottomsurface 54 of window 55 in the outer latch guide 38 which causes-theupper portion of the latch 36y to abut the inner latch guide 39 andthereby bias said portion toward said guide by moving the latch free end47 to a position between the inner and outer guides. In this positionthe latch lock and unlock cycle has been-completed such thatenergization of magnet coil 14 will cause upward movement of thearmature and latch assembly.

FIGS. -8 show another embodiment of the latch assembly 135 which issimilarly associated with an electromagnetic device, here again shown asa contractor, in the manner of FIGS. 1-4. The contactor is representedby contact carrier 105, movable contact 115 and fixed contact 118 pluscontact compression spring 125. Structurally, this latch assemblyembodiment differs -only in the particular latch actuator 137 which isnarrower than the distance between inner latch guide 139 `and outerlatch guide 13S plus the fact that said actuator is pivoted on themounting pin 159 and has a concave cam surface 145 tending toward aV-shape. The remainingv parts of the latch assembly are substantiallythe same as those in FIGS. 1 through 4 and have been correspondinglyindicated by reference numerals in the 100 series.

In operation the sequence is the same as that outlined for FIGS. 1-4,i.e. FIGS. 5-7 correspond respectively to FIGS. 1 and 3-4 in regard tothe position of the armature (not shown), contact carrier 105 and latch136. The pivoted latch actuator 137 rides against the outer latch guide138 during the upward movement of the contact carrier 105 and during apart of the relatively short downward movement when the coil circuit isinterrupted. After the latch lock detent 148 and the inner latch 1guidecatch surface 139 abut in line conta-ct at 162 (see FIG. 6), the latchactuator continues downwardly a distance permitted by tension spring157. This distance is sufficient to separate or release pressure contactbetween the latch 136 and latch actuator 137 so as to permit pivoting oflatch 136 about catch 156 with free end 147 moving toward the innerguide 139; and at the same time pivoting the latch actuator 137 to theinner guide 139 by free end 147 contact with the side walls of theconcave cam surface 145'. In this position (FIG. 7) the tension spring157 biases the latch away from the inner latch guide 139. The downwardmovement of the contact carrier 105 is stopped by a holding plate 146abutting the top of latch 136 in its locked position (FIG. 7), althoughit is again noted that various other expedients can be used to limitsuch downward movement'. Unlocking includes the same Vsequence asout-lined in the operation of FIGS. 14, viz. lifting of the latch 136 topermit latch pivoting about free end 147 and away from the inner guide139, followed by resetting of the latch during lowering of latch 136 andcontact carrier 105 to the position of FIG. 5.

FIGS. 9-12 depict the third latch embodiment and illustrate further theuse of the forwardly extending legs 204 as the beveled catch surface 260for latch lock detent 24S. The combination of contactor and latchassembly is basically the same as that illustrated by FIGS. 1-4 andsimil ar .parts have been referred to by corresponding referencenumerals in a 200 series.

The principal difference injlatch assembly structure of this embodimentis to be found in the latch actuator cam surface 245 which is raisednear a point intermediate the outer latch guide 238 and forwardlyextending leg 204 along with the latch structure at free end 247 whichpermits movement from one side of the latch actuator 237 to the other.Attention is called to the fact that the actuator is Vsubstantially aswide as the distance between outer latch guide 238 and the extended legsupport 204.

In operation, the sequence is substantially similar to that of theprevious embodiments with FIGS. 9-11 showing latch assembly positioncorresponding to those of FIGS. 1 and 3-4. Specifically, latch 236 ismoved upwardly by latch actuator 237 until the latch lock detent 248rises above the beveled catch surface 260 of extended leg 204 (FIG.After the coil current is interrupted and line contact is established at262 (FIG. lO), the latch downward direction 236 pivots about catch 256as latch actuator 237 moves away from latch 236 permitting free latchend 247 to move toward extended leg 204 and over the hump of theactuator cam surface 245. Again, final downward movement of the contactcarrier 205 ends when the holding plate 246 abuts latch 236 in itslocked position (see FIG. l1), although other expedients may be used tolimit this movement, e.g. tension spring .257.

The release of latch 236 is similar -to that of FIGS. 1-4 in that thelatch actuator 237 is raised to separate the latch detent 24S frombeveled surface 260 at which time the bias of tension spring 257 causes-the latch to pivot away from the extended leg 204 about latch free end247. Downward movement of the latch 236 results in resetting the latchas latch protrusion 249 engages the bottom surface 254 of window 255 inouter latch guide 238.

Another possibie use for the present invention is with a switch, e.g.the snap-acting switch illustrated by FIGS. 13-16. Here, an externalforce activates the snap switch while the mechanical latch featurepermits removal of this external force without the normal return of theswitch to its original position.

The particular switch in FIGS. 13-16 is basically that switch shown inU.S. Patent No. 2,796,487; and accordingly, this description will onlyinclude those features of the switch necessary for understanding of themechanical latch feature.

An enclosure 301 provides the outer protection for housing 302 in whichsnap action mechanism 303 is located. This ymechanism 303 includes avertically moving plunger 304 which slides through an aperture 305 ofhousing 302 to abut actuator p-oint 306. The lower end of plunger 304abuts, and thereby transfers motion to, U-shaped, resilient toggle orcontact carrier 307. Carrier 307, in turn, includes a lower spring seat308 which abuts biasing spring 309.

A resilient leaf 312 is hingedly secured to both ends of carrier 307 bymeans of carrier notches 313. This resilient leaf 312 includes movablecontact blades 314 to which two pairs of oppositely mounted, movablecontacts 315 and 316 are attached. Correspondingly, two pairs of lixedcontacts 318 and 319 are located adjacent the movable contacts 315 and316 along with respective contact terminals 320 and terminal screws 321.

Thus, the snap action mechanism 303 operates in the as plunger 304 ismoved by actuator point 306 to thereby move carrier 307 until resilientleaf 312 is snapped from the downward bowedposition of FIG. 13 to theupward bowed position of FIG. 14. As is also evident from the FIGS. 13and 14, biasing spring 309 will return the resilient leaf 312 to itsdownward bowed position when actuator point 306 is relieved of itsmotivating force.

An operating head 324 is located immediately above enclosure 301 for thepurpose of housing an actuator for snap-action mechanism 303 in cavity325. The upper end of cavity 325 is closed by main plunger 326 incombination with a seal 327 which is secured to the operating head 324by means of a force lit between cover plate 328 and st-op plate 329. Aswill be seen from FIGS. 13 and 14, screws 329:1 are used to secure coverplate 328 to the operating head 324. The lower portion of lcavity 325 isfilled in part by fixed, casing guide 330 and partially by the movable,latch assembly 335. Y

It should be noted at this point that although the particular mechanicallatch embodiment to be used with the switch of FIGS, 13-16 is notlimited to the embodiment illustrated, those parts of the mechanicallatch assembly 335 which are common or similar throughout the figureswill be designated hereafter by similar reference numerals differingonly by the use of a 300 number series. Therefore, the latch isdesignated as 336 while the latch actua mechanical latch of the tor isindicated by reference numeral The principal difference to be found inthe mechanical latch assembly 335'of FIGS. 13-16 is the casing 338 whichserves as the housing for latch 336 and latch actuator 337. As will beapparent, this casing 338 is movable (being guided by fixed, casingguide 330) in the same manner as connecting elements 42 are movable inthe previous figures. The latch actuator end of casing 338 is closed byend wall 339. Retaining wire 340, which is integral with main plunger326, retains independent disk 340e within the cavity of main plunger 326and consequently restrains the compressed, overtravel spring 341 whichabuts said disk 340a. The gap between end wall 339 and disk 340a createdby the particular location of retaining wire 340 (see FIG. 13) existswhen a downward external force is not being applied to main plunger 326to thereby enhance therlocking step depicted in FIG. which will bedescribed later.

Compression spring 342 abuts flange 343 of main plunger 326 in order tolocate this main plunger with respect to the latch assembly l335 as wellas to aid biasing spring 309 in the return of snap action mechanism 363(and consequently the latch assembly 335) from the position of FIG. 14to the position of FIG. 13. It should be noted at this point, however,that operati-on of the snap action mechanism 303 may only require spring341 (which would, itself, abut end wall 339) and biasing spring 309 thuseliminating the need for retaining wire 340, disk 340a `and returnspring 342. Moreover, the particular shape of casing 338 may be otherthan that shown in the FIGS. 13-16, e.g. a cylindrical shape.

As is the case in the previously described structure, the latch actuator337 has a cammed surface 345 which abuts the free end 347 of the latch336. In addition, a holding pla-te 346-cut from the wall Iof casing 338is located adjacent the latch lock detent 343 of latch 336 for abutmenttherewith as shown in FIG. l5. The location of holding plate 346 withrespect to latch 336 must be such that the latch 336 will be permittedto move to the position of FIG. 14 and yet establish contact as shown inFIG. 1S.

Further similarity to previously described structure resides in the factthat latch 336 includes a protruding portion 349 including a resetsunface 350. This protr-usion 349 is again capable of extendingexternally from casing 338, viz. into cutout 353 of casing guide 330.With the return of the latch assembly from the position of FIG. 15 tothe position of FIG. 13, it will be seen that reset surface 350 willabut the end 354 of cutout 353 for resetting purposes. Cutout 356 incasing `guide 330 is opposite from cutout 353 and receives latch lockdetent 343 of latch 336; the cutout 356 including a beveled surface 360against which detent 348 abuts for line contact at 361 as shown in FIG.14 and for a lock position as shown in FIG. l5.

Finally, the latch 336 and latch actuator 337 are maintained in anoperating relationship by Imeans of tension spring 357 which is securedto latch 336 by pin 358 and to latch actuator 337 by pin 359. Thisrelationship is best shown in FIG. 16 which also illustrates the rfactthat pin 359 locates latch actuator 337 with respect to the casing 338.Y

End wall 362 completes the Vcasing 338 at an end opposite Vfrom end wall339. As is best seen in FIGS. 13 and 14, the motion transferred fromcasing 338 to snap action mechanism 303 is affected by rod 363, withflange 364, attached to end wall 362 by screw 365. Other means used tosecure said rod 363 to said end wall 362 such as by riveting. Previouslymentioned actuator point 366 is threadedly attached to rod 363 forabutment with the vertically moving plunger 304, while intermediate thelian-ge 364 and end Wall 362 circular diaphragm 366 is held in place bywashers 367 and 368. This circular diaphragm 366 is secured to t-heenclosure d by groove 369 so that the lsnap action mechanism 303 issealed from the operating head casing 304- for obvious reasons,

S eg. to maintain clean operating conditions in mechanisrn 303.

Because the operation of the mechanical latch as used in FIGS. 13-16 issimilar to the operation of the latches previously outlined above, onlya rbrief operational description of this particular latch combination isconsidered ne-cessary. Referring first t-o FIG. 13 Vand beginning withthe switch in the position shown, an external downward force on Amainplunger 326 will result in downward movement of casing 338 ascompression spring 341 forces disk 340e to abut casing end wall 339.Consequently, both latch actuator 337 (through pin 359) and actuatorpoint 306 (through end wall 362 and rod 363) are moved. Suiiicientdownward travell of motivated carrier 307 will cause resilient leaf 312to bow upward thereby opening contacts 316 and 319 while closingcontacts 315 and 318 as shown in FIG. 14. At some point during thisdownward motion, latch lock detent 34S of lat-oh 336 travels belowbeveled surface 360;`whereupon detent 348 is pivoted into the cutoutportion 356 of cylinder 4guide 330 since the latch 336 is biased in thatdirection (see FIG. 14). As will be further noted from FIG. 14, therelationship between latch lock detent 348 and beveled catch surface 360at this point is that of a line contact therebetween as indicated byreference nurneral 361. Depending upon the switch requirements, downwardmovement of the casing 338 may -or may not occur after latch lock detent348 makes contact with beveled surface 360.

When the external force is removed from main plunger 326, a switch, suchas that shown in FIGS. 13-l5 and which has not been equipped with themechanical latch feature of this invention, would return to the positionshown in FIG. 13. However, by means lof the invention described herein,the removal of external force from main plunger 326 `will not change theexisting contact relationship, i.e. movable contacts 315 will remain incontact with fixed contacts 318. Specifically, latch 336 will pivot atthe point of line contact 361 (ie. contact between `latch lock detent348 and beveled catch surface 360) when the casing 338 and main plunger326 are free to be moved upwardly by compression spring 309, aided byreturn spring 342, if available. It is apparent that during thispivoting period, latch 336 is fixed `with respect to casing guide 330 asopposed to lat-ch actuator 337 which may continue its rupward movement.In addition, the gap `between disk 340a and end wall 339 (the gapresulting from the removal of external force from main plunger 326)4permits and encourages this Vupward movement of latch actuator 337 (andcasing 338) while at the same time aiding the pivoting of latch 336 byreducing the pressure between 4latch 336 and latch actuator 337, i.e.only tension spring 357 provides pressure therebetween. As this pivotingof latch 336 continues, latch actuator 337 is rotated about pin 359 bylatch free end 347 which moves along cammed surface 345 until latchactuator `337 abuts the detent side of casing guide 330 as shown in FIG.15.

The net result of this pivoting by latch 336 and latch actuator 337,from the position orf FIG. 14 to that shown in FIG. 15 is a primed latch336 which is biased away from the beveled catch surface 360. The latchassembly 335 is thereby locked `in this position by a surface to surfacecontact relationship between latch detent 348 and beveled catch surface360 again shown in FIG. 15. In

this locked position, `spring 357 may be of suiiicient strength toprevent further upward movement of theV casing 338 and carrier 307although additional locking may be provided by lholding plate 346. Forexample, the embodiment shown in FIG. 15 calls for contact between aholding plate 346 and latch 336 after the latch and latch actuator 337have separated. This separation is encouraged by the gap, whic-hnecessarily eliminates any lack of a restraining force from spring 341,between end wall 339 and disk 340e. It should be noted, however, thatcontact between latch 336 and latch actuator 337 may be maintainedduring this locked position while, at the same time, utilizing holdingplate 346. F-or example, the holding plate 346 may Vbe caused to abutlatch 336 While the latter remains in contact with latch actuator 337 byreshaping the latch 336. It is noted that this construction wouldrequire a force to `restrain the actuator 337 such as could be suppliedby spring 341V to end wall 339. In turn, disk 340g could be therebyeliminated.

To unlatch the latch assembly 345 from the FIG. l position, an externaldownward force on main plunger 326, suicient only to separate the detent348 from beveled end surface 360, is necessary since latch 336 is biasedaway from the beveled catch surface 360` during the latching. Thisslight downward force on main plunger 326 will cause the latch 336 topivot away from the beveled catch surface 360 (about latch free end 347)and permit -compressed spring 309 to return the snap action mechanism303 and the latch assembly 335 to the position shown in FIG. 13 (aidedby return spring 342 if needed and used). During this unlatchingsequence it is also necessary to reset the latch assembly 335; whichresetting is accomplished as reset surface 350 on the protrusion 349 oflatch 336 contacts the end abutment portion 354 of cutout 353 during thereturn of latch assembly 335 to the position of FIG. 13, i.e. theunlatched position.

Thus, it will be evident that the above-described invention provides asignicant improvement in an electromagnetic -device and mechanical latchcombination by providing a more eicient, compact economical andextremely adaptable assembly.

I claim:

1. In ycombination with an electrical switch device including a movableswitching means, a mechanical latch assembly comprising a latch actuatormeans mechanically associated with said movable switching means formovement therewith, independent latch means comprising lock means at oneend and a free end abutting said actuator means for movement therewith,catch means adjacent said mechanical latch assembly for accommodatingsaid lock means in a locking position, resilient means acting to lbiasthe lock means end of the latch means in a direction toward the catchmeans when said free end is away from said catch means and to bias saidlock means end of the latch means away from said catch means when saidfree end is toward s-aid catch means.

2. In combination with an electrical switch device including a movableswitching means, a mechanical latch assembly comprising a latch actuatormeans mechanically associated with said movable switching means formovement therewith, independent latch means comprising lock means at oneend and a free end abutting said actuator means movement therewith,catch means ad-V jacent said mechanical latch assembly for accommodatingsaid lock means in a locking position, resilient means to limit anyseparation between said actuator means and said latch means, saidresilient means further acting to bias the lock means end of the latchmeans in a direction toward the catch means when said free end is awayfrom said catch means and to bias said lock means end of the latch meansaway from said catch means when said free end is toward said catchmeans.

3. In combina-tion with an electrical switch device including a movableswitching means, a mechanical latch assembly means comprising a latchactuator means mehancally associated with Said @lavable Switching mansfor movement therewith and having a cam surface, independent latch'meanscomprising lock means at one end and a free end abutting said actuatormeans at said cam surface for movement therewith, catch means adjacentsaid movable switching means for accommodating said lock means in alocking position, said latch means and said actuator means eachincluding pivotal means to which resilient means are connected so as tolimit any separa-tion of said actuator means from said latch means whilepermitting movement of said free end toward said catch means during saidseparation, said resilient means further acting to bias the lock meansend of the latch means end in a direction toward the catch means whensaid free end is away from said catch means and to bias said lock meansend of the latch means away from said catch means when said free end istoward said catch means.

4. The combination of claim 1 in which said catch means accommodatessaid lock means only when said lock means end of the latch means isbiased toward said catch means.

5. The combination of claim 1 including reset means to move the free endin a direction away from the catch means.

6. vThe combination of claim 1 wherein the lock means is adapted forline contact with said catch means.

7. The combination of claim 1 wherein the latch means has a center ofgravity which encourages latch pivoting about said free end.

8. The combination of claim 1 including a holding means which restrictsmovement of said switching means when said catch means accommodates saidlock means.

9. The combination of claim 8 wherein said holding means comprises aplate means which abuts said latch means when said catch meansaccommodates said lock means.

10. The combination of claim 1 wherein the lock means is adapted forline contact with said catch means and wherein holding means restrictmovement of said switching means when said catch means accommodates saidlatch lock means.

11. The combination of claim 10 wherein said holding means comprises aplate means which abuts said latch means when said catch meansaccommodates said lock means.

12. The combination of claim 3 in which the cam surface of the actuatormeans is concave.

13. The combination of claim 3 in which the actuator means pivots aboutsaid pivotal means thereof in the plane of said free end movement.

14. The combination of claim 13 in which the actuator means cam surfaceis concave.

15. The combina-tion of claim 3 in which a disc means is interposedbetween said latch assembly and a resilient means through which a switchmoving force is transferred whereby said -discY means abuts said latchassembly when said force is exerted.

References Cited bythe Examiner UNITED STATES PATENTS 2,749,415 6/1956Davis 20o- 167 3,201,545 8/1965 Kruzie 335-170 3,244,836 4/1966 Myers 120o-16a ROBERT K. SCHAEFER, Primary vEaaminer. I-I. JONES, AssistantExaminer.A

1. IN COMBINATION WITH AN ELECTRICAL SWITCH DEVICE INCLUDING A MOVABLESWITCHING MEANS, A MECHANICAL LATCH ASSEMBLY COMPRISING A LATCH ACTUATORMEANS MECHANICALLY ASSOCIATED WITH SAID MOVABLE SWITCHING MEANS FORMOVEMENT THEREWITH, INDEPENDENT LATCH MEANS COMPRISING LOCK MEANS AT ONEEND AND A FREE END ABUTTING SAID ACTUATOR MEANS FOR MOVEMENT THEREWITH,CATCH MEANS ADJACENT SAID MECHANICAL LATCH ASSEMBLY FOR ACCOMMODATINGSAID LOCK MEANS IN A LOCKING POSITION, RESILIENT MEANS ACTING TO BIASTHE LOCK MEANS END OF THE LATCH MEANS IN A DIRECTION TOWARD THE CATCHMEANS WHEN SAID FREE END IS AWAY FROM SAID CATCH MEANS AND TO BIAS SAIDLOCK MEANS END OF THE LATCH MEANS AWAY FROM SAID CATCH MEANS WHEN SAIDFREE END IS TOWARD SAID CATCH MEANS.